二维单晶WO₂微纳米片的制备及光电特性研究

Study on Preparation and Photoelectric Properties of Two-Dimensional Single-Crystal WO₂ Micro/Nano Plates

摘要: 本文利用WSe₂辅助化学气相沉积(CVD)方法，开展了大尺度二维单晶WO₂微纳米片的低温制备工艺研究，分析了生长时间、温度、WO₃和WSe₂粉末质量比对单晶WO₂微纳米片的形貌、结构及生长尺度等特性的影响。光学显微镜和扫描电镜分析表明，合成的单晶WO₂微纳米板具有良好的多面菱形几何结构，横向尺寸可达几微米至几十微米，厚度为几个nm到十几个nm。同时，制备出的二维单晶WO₂微纳米片表面平整光滑，边界清晰，厚度均匀，还具有一定的透光性。研究发现，最佳的制备参数为管式炉中心温度为1300℃，生长时间为30 min，WO₃和WSe₂粉末质量比为4:1。对二维单晶WO₂微纳米片的I-V特性及光电响应特性测试发现，二维单晶WO₂微纳米片的导电类型呈现出明显的金属特性，并对辐照光源亮度的变化表现出较好的光响应特性。

Abstract: In this work, the low-temperature preparation technology of large-scale two-dimensional single-crystal WO₂ mi-cro/nano plates was investigated using the WSe₂-assisted Chemical Vapor Deposition (CVD) method. And the influencing factors of the growth time, temperature, and mass ratio of WO₃ and WSe₂ powder on the morphology, microstructure and growth scale of single-crystal WO₂ micro/nano plates were analyzed, respectively. Optical microscopy and scanning electron microscopy demonstrate that the synthesized single-crystal WO₂ micro/nano plates exhibit a well-faceted rhombic geometry with a lateral dimension up to several microns to tens of microns. Moreover, the thickness ranging from several nm to a dozen nm can be achieved. The preparation of WO₂ micro/nano plates showed smooth surface, clear boundary, uniform thickness, and certain light transmittance. It was found that the furnace center temperature of 1300˚C, a growth time of 30 minutes, and a mixed powder of WO₃ and WSe₂ with a mass ratio of 4:1 were the optimum preparation parameters. Simultaneously, the I-V and photoelectric response performances of WO2 micro/nano plates were measured. The results displayed that the conductive type of synthesized single-crystal WO₂ micro/nano plates exhibited obvious metallic characteristics, as well as good photoresponse properties to the change in brightness of the irradiation source.